Conger
More on Conger (Marine Education & Research Society [MERS])
YouTube
We first documented this novel feeding strategy for 2 individuals around northeast Vancouver Island in 2011. As of November 2024, we know of 34 Humpback Whales who have learned to use this strategy under specific conditions.
Trap-feeding is where some Humpbacks set a trap for juvenile herring when juvenile herring are in small, diffuse schools.
The fish then collect near, or in, the mouth of the Humpback to escape predation by diving birds (most often Common murres and Rhinoceros Auklets).
The Humpbacks then spin and/or use their pectoral flippers to push the fish into their mouths. This feeding strategy uses less energy than when Humpbacks lunge-feed on greater concentrations of juvenile herring.
More on Conger (Marine Education & Research Society [MERS])
Humpbacks are also well known for “bubble-net feeding.” With this strategy, teams of whales work together to corral fish and this includes a member of the team blowing a net of bubbles to stop the fish from escaping.
This is not a strategy employed by Humpbacks around northeast Vancouver Island as the current would dissipate the bubbles. It is used by Humpbacks around BC’s central coast and further to the north. Only occasionally will individual Humpback Whales around northeast Vancouver Island use bubbles to corral fish (not teams) when there is no current i.e. on slack tide or in a back eddy.
MERS’ research supports that the Humpbacks of northeastern Vancouver Island are lunge-feeding specialists on juvenile herring, with some of the whales having learned this new feeding strategy—"trap-feeding" when the fish are in smaller, less concentrated schools.
When the whales are trap-feeding, it is often very difficult to see their dorsal fins or flukes to identify them. This has led to our compiling a catalogue of their mouths so that we can identify them by the distinctive markings on their jaws.
Octopus (BBC)
Octopus opens jar
Two hours of BBC Earth, narrated by David Attenborough
Pangea (USGS)
From about 300-200 million years ago (late Paleozoic Era until the very late Triassic), the continent we now know as North America was contiguous with Africa, South America, and Europe. They all existed as a single continent called Pangea. Pangea first began to be torn apart when a three-pronged fissure grew between Africa, South America, and North America. Rifting began as magma welled up through the weakness in the crust, creating a volcanic rift zone. Volcanic eruptions spewed ash and volcanic debris across the landscape as these severed continent-sized fragments of Pangea diverged. The gash between the spreading continents gradually grew to form a new ocean basin, the Atlantic. The rift zone known as the mid-Atlantic ridge continued to provide the raw volcanic materials for the expanding ocean basin.
Pangea (USGS)
Meanwhile, North America was slowly pushed westward away from the rift zone. The thick continental crust that made up the new east coast collapsed into a series of down-dropped fault blocks that roughly parallel today's coastline. At first, the hot, faulted edge of the continent was high and buoyant relative to the new ocean basin. As the edge of North America moved away from the hot rift zone, it began to cool and subside beneath the new Atlantic Ocean. This once-active divergent plate boundary became the passive, trailing edge of westward moving North America. In plate tectonic terms, the Atlantic Plain is known as a classic example of a passive continental margin.
Today, the Mesozoic and Cenozoic sedimentary rock layers that lie beneath much of the coastal plain and fringing continental shelf remain nearly horizontal.
Holocene (Anthropocene)—National Geographic
Earth’s history is divided into a hierarchical series of smaller chunks of time, referred to as the geologic time scale. These divisions, in descending length of time, are called eons, eras, periods, epochs, and ages.
These units are classified based on Earth’s rock layers, or strata, and the fossils found within them. From examining these fossils, scientists know that certain organisms are characteristic of certain parts of the geologic record. The study of this correlation is called stratigraphy.
Officially, the current epoch is called the Holocene, which began 11,700 years ago after the last major ice age. However, the Anthropocene Epoch is an unofficial unit of geologic time, used to describe the most recent period in Earth’s history when human activity started to have a significant impact on the planet’s climate and ecosystems.
The word Anthropocene is derived from the Greek words anthropo, for “man,” and cene for “new,” coined and made popular by biologist Eugene Stormer and chemist Paul Crutzen in 2000.
Holocene (Anthropocene)—National Geographic
Scientists still debate whether the Anthropocene is different from the Holocene, and the term has not been formally adopted by the International Union of Geological Sciences (IUGS), the international organization that names and defines epochs. The primary question that the IUGS needs to answer before declaring the Anthropocene an epoch is if humans have changed the Earth system to the point that it is reflected in the rock strata.
To those scientists who do think the Anthropocene describes a new geological time period, the next question is, when did it begin, which also has been widely debated. A popular theory is that it began at the start of the Industrial Revolution of the 1800s, when human activity had a great impact on carbon and methane in Earth’s atmosphere.
Others think that the beginning of the Anthropocene should be 1945, when humans tested the first atomic bomb, and then dropped them on Hiroshima and Nagasaki, Japan. The resulting radioactive particles were detected in soil samples globally.
In 2016, the Anthropocene Working Group agreed that the Anthropocene is different from the Holocene, and began in the year 1950 when the Great Acceleration, a dramatic increase in human activity affecting the planet, took off.
Great Acceleration
The Great Acceleration refers to the dramatic increase in human activities and their impact on the Earth's natural systems, beginning around the mid-20th century (post-1950). This period is characterized by rapidly rising population, energy use, economic output, and resource consumption, leading to profound global environmental changes such as increased greenhouse gas emissions, deforestation, and loss of biodiversity.
This term is closely associated with the Anthropocene, a proposed geological epoch defined by significant human alteration of the planet.
The Holocene Epoch (UC, Berkeley)
The Holocene is the name given to the last 11,700 years of Earth's history—the time since the end of the last major glacial epoch, or "ice age." Since then, there have been small-scale climate shifts—notably the "Little Ice Age" between about 1200 and 1700 A.D. But in general, the Holocene has been a relatively warm period in between ice ages.
Another name for the Holocene sometimes used is the Anthropocene, the "Age of Man." This is somewhat misleading: humans of our own subspecies, Homo sapiens, had evolved and dispersed all over the world well before the start of the Holocene. Yet the Holocene has witnessed all of humanity's recorded history and the rise and fall of all its civilizations.
Humanity has greatly influenced the Holocene environment; while all organisms influence their environments to some degree, few have ever changed the globe as much, or as fast, as our species is doing.
The Holocene Epoch (UC, Berkeley)
The vast majority of scientists agree that human activity is responsible for "global warming," an observed increase in mean global temperatures that is still going on. Habitat destruction, pollution, and other factors are causing an ongoing mass extinction of plant and animal species.
According to some projections, 20% of all plant and animal species on Earth will be extinct within the next 25 years.
Key Characteristics
Warming Climate: The epoch began with the end of the Pleistocene ice age, leading to rising global temperatures and the retreat of glaciers.
Human Civilization: All of recorded human history, including the rise of complex societies and technological advancements, occurred during the Holocene.
Earth's Surface: Melting glaciers caused sea levels to rise by over 120 meters, transforming coastal environments.
Holocene Epoch (AI)
The Holocene is divided into three stages, identified by shifts in climate and geological events:
Greenlandian Stage (11,700 to 8,300 years ago): This initial warming period is defined by ice core data from Greenland.
Northgrippian Stage (8,300 to 4,200 years ago): A significant cooling event in the North Atlantic, tied to disruptions in ocean circulation from melting freshwater.
Meghalayan Stage (4,200 years ago to present): Began with a 200-year period of worldwide drought and cooling, documented in a stalagmite from a cave in India.
Holocene Epoch (AI)
The Holocene is sometimes called the Anthropocene "Age of Man" because of the extensive and transformative impact humans have had on the planet's ecosystems, climate, and biodiversity.
Sixth Mass Extinction:
Human activity has led to a significant increase in extinction rates, a phenomenon known as the Holocene or Sixth Mass Extinction.
Emergence of the Anthropocene:
Due to the overwhelming effects of human activities such as nuclear testing, pollution, agriculture, and carbon emissions, the scientific community is considering whether the Holocene has been superseded by a new epoch, the Anthropocene.
Earth's extinctions
Earth's extinctions are mass events that cause rapid, widespread loss of biodiversity, and there have been five major ones in Earth's history: the Ordovician, Devonian, Permian-Triassic, Triassic-Jurassic, and Cretaceous-Paleogene (K-Pg) extinctions, the last of which famously ended the age of dinosaurs.
These events are driven by factors like asteroid impacts, massive volcanic activity, and climate change, which disrupt ecosystems and create opportunities for new species to evolve.
Many scientists believe Earth is currently undergoing a sixth, human-caused mass extinction event.
https://oumnh.ox.ac.uk/earths-five-mass-extinctions
Earth's extinctions
The Five Major Mass Extinctions
1. Ordovician Period (around 440 million years ago): The mass extinction at the end of the Ordovician Period was caused by large-scale glaciation and a global fall in sea levels. Up to 85 per cent of shallow marine species died out, including many trilobites, bryozoans, brachiopods, bivalves, corals and graptolites.
2. End of Devonian Period (around 370 million years ago): Many marine species were lost in the Devonian mass extinction. Reef-building corals and bony armored "fish" were particularly hard-hit. Some marine animals, such as crinoids, were not badly affected, though we do not yet know why. Understanding why the mass extinction affected some species more than others is important in assessing today’s biodiversity crisis. It was caused by a complex series of events including ocean oxygen depletion and potentially widespread volcanic activity, and primarily impacted ocean life.
Earth's extinctions
The Five Major Mass Extinctions
3. Permian Period (around 252 million years ago): Also known as "The Great Dying," it removed up to 96% of marine species and around 70% of land species. Trilobites, sea scorpions, and rugose and tabulate corals all disappeared forever. The main cause was the global warming that followed large-scale volcanic eruptions.
4. End of the Triassic period (around 201 million years ago): It saw the demise of phytosaurs and many groups of "crocodile-like" archosaurs, which paved the way for the domination of the dinosaurs in the Jurassic and Cretaceous. Conodonts – small but abundant jawless marine vertebrates – were wiped out completely. This event, which eliminated many large land animals, including the ancestors of dinosaurs, was possibly due to the breakup of the supercontinent Pangea and extensive volcanic eruptions.
Earth's extinctions
The Five Major Mass Extinctions
5. Cretaceous-Paleogene (K-Pg) Extinction (around 66 million years ago): Perhaps the best known of all mass extinctions occurred at the end of the Cretaceous Period. All dinosaurs other than birds disappeared, along with many other large reptile groups, such as pterosaurs, plesiosaurs and mosasaurs. Land plants and herbivorous insects also suffered major losses. The main cause was a huge meteorite impact in what is now Mexico. It triggered widespread volcanic activity and climate disruption, ending the reign of the non-avian dinosaurs.
6. Human activity has driven extinction rates to hundreds of times higher than the background rate, threatening Earth’s next mass extinction. Some experts have argued that the sixth mass extinction is already underway. Since the 17th century, extinction rates have accelerated rapidly. Perhaps the greatest threat to biodiversity in the modern era is climate change.
Earth's extinctions
The Bramble Cay Melomys is the first mammal known to have become extinct due to human-caused global warming. The species was once endemic to a small island in the Torres Strait, north of Australia.
Recorded sightings of the melomys from the 19th century describe the population flourishing. But by the end of the 20th century, alarm bells were ringing. In 2013, it was reported that the melomys' range had been reduced to an area of just 4-5 hectares. As rising sea levels continued to wash away vegetation, the species was left without enough food or shelter to survive, and by 2019 it was declared extinct.
Mass extinctions
Mass Extinctions, Donald Davis--NASA
Causes of Extinctions
Mass extinctions are characterized by sudden, dramatic changes to the planet's systems, leading to widespread species loss faster than organisms can adapt or evolve. Key factors include:
Asteroid or Comet Impacts: These can throw vast amounts of dust into the atmosphere, blocking sunlight, and causing global cooling, or trigger other climate catastrophes.
Volcanic Activity: Enormous and prolonged volcanic eruptions can release gases that dramatically alter the climate, ocean chemistry, and atmospheric conditions.
Climate Change: Rapid shifts in temperature, ocean acidification, and changes in geography can make habitats uninhabitable for many species.
The Sixth Mass Extinction: Many scientists believe that Earth is currently experiencing a sixth mass extinction, largely due to human activities like habitat destruction and climate change, which are causing extinction rates to far exceed the normal background levels.
Extinction during Permian period
Scientists have debated until now what made Earth's oceans so inhospitable to life that some 96 percent of marine species died off at the end of the Permian period. New research shows the "Great Dying" was caused by global warming that left ocean animals unable to breathe.
Causes of Extinctions (Stanford Doerr School of Sustainability)
The largest extinction in Earth's history marked the end of the Permian period, some 252 million years ago. Long before dinosaurs, our planet was populated with plants and animals that were mostly obliterated after a series of massive volcanic eruptions in Siberia.
Fossils in ancient seafloor rocks display a thriving and diverse marine ecosystem, then a swath of corpses. Some 96 percent of marine species were wiped out during the "Great Dying," followed by millions of years when life had to multiply and diversify once more.
What has been debated until now is exactly what made the oceans inhospitable to life – the high acidity of the water, metal and sulfide poisoning, a complete lack of oxygen, or simply higher temperatures.
New research from the University of Washington and Stanford University combines models of ocean conditions and animal metabolism with published lab data and palaeoceanographic records to show that the Permian mass extinction in the oceans was caused by global warming that left animals unable to breathe.
Causes of Extinctions (Stanford Doerr School of Sustainability)
As temperatures rose and the metabolism of marine animals sped up, the warmer waters could not hold enough oxygen for them to survive.
The study is published in the Dec. 7 issue of Science.
"This is the first time that we have made a mechanistic prediction about what caused the extinction that can be directly tested with the fossil record, which then allows us to make predictions about the causes of extinction in the future," said first author Justin Penn, a UW doctoral student in oceanography.
"We’ve never been able to gain such insight into exactly how and why different stressors affected different parts of the global ocean. ” Erik Sperling, Asst. Prof., Geological Sciences.
Causes of Extinctions (Stanford Doerr School of Sustainability)
Researchers ran a climate model with Earth's configuration during the Permian, when the land masses were combined in the supercontinent of Pangea. Before ongoing volcanic eruptions in Siberia created a greenhouse-gas planet, oceans had temperatures and oxygen levels similar to today's. The researchers then raised greenhouse gases in the model to the level required to make tropical ocean temperatures at the surface some 10 degrees Celsius (20 degrees Fahrenheit) higher, matching conditions at that time.
The model reproduces the resulting dramatic changes in the oceans. Oceans lost about 80 percent of their oxygen. About half the oceans' seafloor, mostly at deeper depths, became completely oxygen-free.
Causes of Extinctions (Stanford Doerr School of Sustainability)
To analyze the effects on marine species, the researchers considered the varying oxygen and temperature sensitivities of 61 modern marine species – including crustaceans, fish, shellfish, corals and sharks – using published lab measurements. The tolerance of modern animals to high temperature and low oxygen is expected to be similar to Permian animals because they had evolved under similar environmental conditions. The researchers then combined the species' traits with the paleoclimate simulations to predict the geography of the extinction.
"Very few marine organisms stayed in the same habitats they were living in – it was either flee or perish," said second author Curtis Deutsch, a UW associate professor of oceanography.
According to study co-author Jonathan Payne, a professor of geological sciences at Stanford’s School of Earth, Energy & Environmental Sciences (Stanford Earth), “The conventional wisdom in the paleontological community has been that the Permian extinction was especially severe in tropical waters.” Yet the model shows the hardest hit were organisms most sensitive to oxygen found far from the tropics. Many species that lived in the tropics also went extinct in the model, but it predicts that high-latitude species, especially those with high oxygen demands, were nearly completely wiped out.
Causes of Extinctions (Stanford Doerr School of Sustainability)
To make matters worse, unsustainable food production and consumption are significant contributors to greenhouse gas emissions that are causing atmospheric temperatures to rise, wreaking havoc across the globe. Climate change is causing everything from severe droughts to more frequent and intense storms.
It also exacerbates the challenges associated with food production that stress species, while creating conditions that make their habitats inhospitable. Increased droughts and floods have made it more difficult to maintain crops and produce sufficient food in some regions.
The intertwined relationships among the food system, climate change, and biodiversity loss are placing immense pressure on our planet.
World Wildlife Fund (WWF)
Why should we care about mass extinction?
Species do not exist in isolation; they are interconnected. A single species interacts with many other species in specific ways that produce benefits to people, like clean air, clean water, and healthy soils for efficient food production.
When one species goes extinct in an ecosystem or its population numbers decline so significantly that it cannot sustain its important function, other species are affected, impacting the way the ecosystem functions and the benefits it provides. And the potential for species extinction rises.
Monitoring these trends is vital because they are a measure of overall ecosystem health. Serious declines in populations of species are an indicator that the ecosystem is breaking down, warning of a larger systems failure.
World Wildlife Fund (WWF)
What can we do to stop mass extinction?
Urgent action is needed if we are to curb human impacts on biodiversity.
Paris Agreement. We can ramp up our commitments to cutting carbon emissions under the Paris Agreement and limit global warming to 1.5 degrees Celsius.
30X30. Our leaders can support the America the Beautiful initiative to conserve 30% of US lands and waters by 2030.
Kunming-Montreal Agreement. US leadership can play a critical role alongside 195 other countries in conserving at least 30% of lands, inland waters, and oceans worldwide.
Grassroots action. While the federal government can set high-level policies to conserve nature, businesses, communities, and individuals have a powerful role to play in shifting corporate behavior with their consumer choices and demanding accountability from political leaders.
World Wildlife Fund (WWF)
Currently, the species extinction rate is estimated between 1,000 and 10,000 times higher than natural extinction rates—the rate of species extinctions that would occur if we humans were not around. While extinctions are a normal and expected part of the evolutionary process, the current rates of species population decline and species extinction are high enough to threaten important ecological functions that support human life on Earth, such as a stable climate, predictable regional precipitation patterns, and productive farmland and fisheries.
If we do not course correct, we will continue to lose life-sustaining biodiversity at an alarming rate. These losses will, at best, take decades to reverse, resulting in a planet less able to support current and future generations.
World Wildlife Fund (WWF)
What can we do to stop mass extinction?
Urgent action is needed if we are to curb human impacts on biodiversity.
Paris Agreement. We can ramp up our commitments to cutting carbon emissions under the Paris Agreement and limit global warming to 1.5 degrees Celsius.
30X30. Our leaders can support the America the Beautiful initiative to conserve 30% of US lands and waters by 2030.
Kunming-Montreal Agreement. US leadership can play a critical role alongside 195 other countries in conserving at least 30% of lands, inland waters, and oceans worldwide.
Grassroots action. While the federal government can set high-level policies to conserve nature, businesses, communities, and individuals have a powerful role to play in shifting corporate behavior with their consumer choices and demanding accountability from political leaders.
Associated Links
Link: Oxford University Museum of Natural History
Video—Using museums to prevent extinction
5 Mass Extinctions--NASA, Donald Davis
PBS: Nova (Pangea)
Correctives—Mangroves (U.S.—EPA)
Mangroves Support Important Marine Ecosystems
The U.S. Virgin Islands (USVI) are part of the Virgin Islands archipelago in the Caribbean. Known for their beautiful beaches and ecotourism activities, the islands attract many visitors and tourism is a key driver in the local economy.
In addition to its iconic sandy beaches, the USVI are home to a number of important ecosystems, including coral reefs, subtropical forests, seagrass beds, and mangroves. Mangroves provide important ecosystem benefits, such as nutrient filtration, shoreline protection, water and air quality preservation, and recreation. They also provide important habitat for marine and terrestrial wildlife.
By retaining sediment in their roots, mangroves stabilize shorelines, helping to protect coastal communities from flooding and erosion.
Correctives—Mangroves (U.S.—EPA)
Mangrove roots also have the ability to trap and filter sediment and runoff, including heavy metals, that are harmful to coral reefs. Known as a “blue carbon” ecosystem, mangroves absorb carbon dioxide from the atmosphere and store it in their roots, leaves, and soils, which offsets overall carbon dioxide emissions and helps to mitigate climate change.
The USVI are home to a unique coexisting mangrove-coral ecosystem located in the four mangrove-lined bays of Hurricane Hole, St. John. Though mangroves are often viewed as an unsuitable habitat for coral, the mangroves in Hurricane Hole support a thriving coral ecosystem, while neighboring reefs have experienced large declines. Scientists believe this could be because the mangroves offer shade to the coral, reducing stressors like heat.
More than 30 coral species have been identified growing on or near mangrove prop roots (arching roots that descend from the trunk and branches into the water) in Hurricane Hole. In 2005 and 2006, the tropical Atlantic and Caribbean experienced record losses of coral reefs due to high ocean temperatures. The size of many coral colonies in Hurricane Hole indicate that they survived these catastrophic bleaching and disease events, leading scientists to believe the mangroves provide other species with refuge from the impacts of climate change.
All about mangroves: https://www.youtube.com/watch?v=n3N__vxSBdI
Correctives—Grasslands
UC, Davis: Grasslands More Reliable Carbon Sink Than Trees.
In Wildfire-Prone California, Grasslands a Less Vulnerable Carbon Offset Than Forests
Forests have long served as a critical carbon sink, consuming about a quarter of the carbon dioxide pollution produced by humans worldwide. But decades of fire suppression, warming temperatures and drought have increased wildfire risks—turning California’s forests from carbon sinks to carbon sources.
A study from UC Davis found that grasslands and rangelands are more resilient carbon sinks than forests in 21st century California. As such, the study indicates they should be given opportunities in the state’s cap-and-and trade market, which is designed to reduce California’s greenhouse gas emissions to 40 percent below 1990 levels by 2030.
The findings, published in the journal Environmental Research Letters, could inform similar carbon offset efforts around the globe, particularly those in semi-arid environments, which cover about 40 percent of the planet.
“Looking ahead, our model simulations show that grasslands store more carbon than forests because they are impacted less by droughts and wildfires,” said lead author Pawlok Dass, a postdoctoral scholar in Professor Benjamin Houlton’s lab at UC Davis. “This doesn’t even include the potential benefits of good land management to help boost soil health and increase carbon stocks in rangelands.”
Correctives—Grasslands
Unlike forests, grasslands sequester most of their carbon underground, while forests store it mostly in woody biomass and leaves. When wildfires cause trees to go up in flames, the burned carbon they formerly stored is released back to the atmosphere. When fire burns grasslands, however, the carbon fixed underground tends to stay in the roots and soil, making them more adaptive to climate change.
“In a stable climate, trees store more carbon than grasslands,” said co-author Houlton, director of the John Muir Institute of the Environment at UC Davis. “But in a vulnerable, warming, drought-likely future, we could lose some of the most productive carbon sinks on the planet. California is on the frontlines of the extreme weather changes that are beginning to occur all over the world. We really need to start thinking about the vulnerability of ecosystem carbon, and use this information to de-risk our carbon investment and conservation strategies in the 21st century.”
The current path of global carbon emissions reveals grasslands as the only viable net carbon dioxide sink through 2101. And grasslands continue to store some carbon even during extreme drought simulations.
Correctives—Grasslands
Trees are still critical. The study does not suggest that grasslands should replace forests on the landscape or diminish the many other benefits of trees. Rather, it indicates that, from a cap-and-trade, carbon-offset perspective, conserving grasslands and promoting rangeland practices that promote reliable rates of carbon sequestration could help more readily meet the state’s emission-reduction goals.
As long as trees are part of the cap-and-trade portfolio, protecting that investment through strategies that would reduce severe wildfire and encourage drought-resistant trees, such as prescribed burns, strategic thinning and replanting, would likely reduce carbon losses, the authors note. But the study itself did not consider in its models forest management strategies that reduce wildfire threats.
Since 2010, about 130 million trees have died in California forests due to high tree densities combined with climate change, drought and bark beetle infestation, the U.S. Forest Service reports. Eight of the state’s 20 most destructive fires have occurred in the past four years, with the five largest fire seasons all occurring since 2006.
Correctives—Grasslands
“Trees and forests in California are a national treasure and an ecological necessity,” Houlton said. “But when you put them in assuming they’re carbon sinks and trading them for pollution credits while they’re not behaving as carbon sinks, emissions may not decrease as much as we hope.”
https://www.youtube.com/watch?v=k3MBLIqePik&t=2 (funded by NSF)
Correctives—Grasslands
From Minnesota Board of Water and Soil Resources
Prairie systems contain much more soil organic carbon than other ecosystems due to rooting characteristics of the vegetation that grows there. These systems have adapted to frequent fire and grazing by developing deep root systems. Grasslands and shrubland carbon stock make up 34% of all carbon in the U.S. Great Plains region.
Native grassland species have extensive root systems, some growing up to 15 feet deep. In fact, most of native grassland species' biomass is found below ground. Grasslands dominated by native species store more carbon in soil than those dominated by non-native species. Native prairie species are known to have up to twice the deep root biomass of introduced species.
Deep root systems deposit carbon into deep soil layers, important because the rate of carbon sequestration increases with soil depth. Deep roots of native species are more likely to contribute to very stable carbon pools via the exchange of plant sugars for nutrients with associated soil microbial life in the root zones.
Correctives—Grasslands
From Minnesota Board of Water and Soil Resources
Biomass of soil microbes increases with plant species diversity. Late successional plant diversity increases carbon in the root zones as more diverse, perennial plant communities promote more diverse micro-organisms which contribute to long term, below ground carbon storage.
Each year as much as one-half of a native prairie plant's root system dies and regenerates. This annual root turnover contributes large amounts of organic materials to the soil system. Living roots also contribute organic material through exudation of carbohydrate-containing compounds and sloughing dead cells. Root associative fungi and bacteria exchange carbohydrates for minerals and water, over time shifts in community assembly shift towards fungal dominated biota. Root-derived soil organic carbon is well protected against oxidation and decay because it is buried deep in the soil profile.
Correctives—Grasslands
From Minnesota Board of Water and Soil Resources
Disturbance, depending on the type, can either reduce or enhance soil organic carbon accumulation. Disturbance to prairie soils from tillage results in losses of soil organic carbon from oxidation to the atmosphere in the form of carbon dioxide. Some prairie soils have lost more than 50% of their organic matter as a result of breaking the sod and tillage for crop production. Soil organic carbon is protected from oxidation and release to the atmosphere when disturbance from tillage is eliminated.
Naturally occurring periodic fires increase the carbon storage of prairies. Fire causes oxidation of organic carbon while simultaneously stimulating root growth and increasing organic matter additions to the soil. Fire results in a net gain of carbon to the soil system because enhanced root growth exceeds oxidative losses. Woody plant encroachment is controlled by periodic fire, but could actually increase carbon sequestration while altering grassland composition.
Correctives—Grasslands
From Minnesota Board of Water and Soil Resources
Managed grazing can also increase carbon storage, rotational grazing practices can stimulate root growth. This practice is most effective at building soil carbon stocks when grazing management prevents overgrazing and over compaction which can reverse the sequestration rates of grassland soils by depleting vegetation and preventing healthy vegetative growth.
Next Week
Discussion of The Sixth Extinction